Unmanned aerial vehicle ground target motion monitoring method

Abstract

The invention relates to a method for monitoring the motion of a ground target by an unmanned aerial vehicle, and the method comprises the steps: S1, obtaining the three-dimensional coordinates of the ground target in an earth coordinate system according to a set time interval; s2, based on a conversion relation between an earth coordinate system and a horizontal plane coordinate system, calculating a horizontal plane movement direction of the ground target according to two three-dimensional coordinates of the ground target at adjacent set time intervals; and S3, according to the two three-dimensional coordinates of the ground target in the adjacent set time intervals, calculating the moving distance of the ground target in the adjacent set time intervals, and according to the set time intervals, calculating the moving speed of the ground target.

Description

Technical Field

[0001] The present invention relates to the technical field of unmanned aerial vehicle monitoring, and in particular to a method for monitoring the motion of a ground target by an unmanned aerial vehicle. Background Art

[0002] With the widespread application of unmanned aerial vehicles, the positioning and navigation technology of unmanned aerial vehicles has also received extensive attention. In the navigation of unmanned aerial vehicles, the motion monitoring of ground targets by unmanned aerial vehicles is an important basis for achieving the mission.

[0003] With the support of modern high-tech information technology, as the level of sensors, communications, and computing intelligence continues to improve, the real-time positioning of drones on ground targets has been basically achieved. At the same time, with the continuous expansion of drone application scenarios, the requirements for high-precision motion monitoring of drones on ground targets are also increasing. Therefore, it is necessary to provide an accurate drone-to-ground target motion monitoring method. Summary of the invention

[0004] The present invention provides a method for monitoring the motion of a ground target by using a UAV, which can obtain the three-dimensional coordinates of the ground target in the earth coordinate system according to a set interval, and accurately calculate the motion speed of the ground target according to a set formula, thereby providing technical support for further navigation.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present application provides a method for monitoring ground target motion by a drone, the method comprising:

[0007] S1, obtaining the three-dimensional coordinates of the ground target in the earth coordinate system according to the set time interval;

[0008] S2, based on the conversion relationship between the earth coordinate system and the horizontal plane coordinate system, according to the two three-dimensional coordinates of the ground target in adjacent set time intervals, calculating the horizontal plane movement direction of the ground target;

[0009] S3, calculating the moving distance of the ground target in adjacent set time intervals according to the two three-dimensional coordinates of the ground target in adjacent set time intervals, and calculating the moving speed of the ground target according to the set time intervals.

[0010] In one implementation, in S1, the set time interval is the time interval between adjacent video frames of the drone capturing images of the ground target.

[0011] In one implementation, in S1, the three-dimensional coordinates include the latitude and longitude coordinates of the ground target.

[0012] In one implementation, the horizontal plane coordinate system adopts a 360° direction method, where the due north direction is 0° and the angle value gradually increases in a clockwise direction.

[0013] In one implementation, in S3, the calculation formula of the moving distance is:

[0014]

[0015] Wherein, d is the moving distance, r is the radius of the earth; (lat1, lon1) and (lat2, lon2) are respectively the two longitude and latitude coordinates of the adjacent set time intervals;

[0016] △lat=lat2-lat1 is the dimensionality difference;

[0017] △lon=lon2-lon1 is the difference in longitude.

[0018] The technical solution of the present invention provides a method for monitoring the motion of ground targets by using a UAV, which uses a monocular UAV to locate ground moving targets by taking photos at equal time intervals. The premise of the present invention is that the three-dimensional coordinates of the target in each photo have been obtained, and the time interval between the photos taken by the UAV during flight is known. The present invention can obtain the motion direction and speed of the target through certain calculations. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The figure is a flow chart of an application scenario of the method for monitoring ground target motion by a UAV in an embodiment of the present invention. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution of the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiment of the present invention. Obviously, the described embodiment is a part of the embodiment of the present invention, not all of the embodiments. Based on the described embodiment of the present invention, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0021] In view of the defects and problems of the prior art, the present application provides a method for monitoring the motion of a ground target by a UAV, the method comprising:

[0022] S1, obtaining the three-dimensional coordinates of the ground target in the earth coordinate system according to the set time interval;

[0023] Specifically, in an optional calculation method, the earth can be regarded as a standard sphere. The three-dimensional coordinates can be simplified to two-dimensional longitude and latitude coordinates. In this way, the calculation is faster.

[0024] In the embodiment of the present invention, the real-time positioning of the ground target by the UAV has been basically realized, and the latitude and longitude coordinates of the ground target can be obtained in real time according to the set time interval.

[0025] For example, a text file recording the three-dimensional data of a ground target can be sent to a drone. The drone reads the data in the text file at a set time interval, performs data parsing (for example, through a string segmentation function), and obtains the three-dimensional coordinates.

[0026] In one embodiment, the set time interval is the time interval between adjacent video frames of the drone capturing images of the ground target. The drone takes pictures of the ground target at the set time interval, and an image of the ground target can be obtained at each set time interval, and the ground target (or its image center) occupies a different pixel point in different images.

[0027] In another optional calculation method, the three-dimensional coordinates of the earth coordinate system may include the distance from the ground target to the center of the earth, the angle between the ground target and the center of the earth and the polar axis of the North Pole of the earth, and the angle relative to the equatorial plane. This mode takes into account that the earth is not a standard sphere, and the calculation is more accurate.

[0028] S2, based on the conversion relationship between the earth coordinate system and the horizontal plane coordinate system, according to the two three-dimensional coordinates of the ground target in adjacent set time intervals, calculating the horizontal plane movement direction of the ground target;

[0029] Specifically, the horizontal plane coordinate system adopts a 360° direction method, with due north being 0° and the angle value gradually increasing in a clockwise direction.

[0030] Assuming that the earth is a sphere, the calculation of the movement direction is implemented by the following code: Wherein, (lat1, lon1) and (lat2, lon2) are two longitude and latitude coordinates corresponding to the adjacent pixel points of the set time interval.

[0031] double calculateDirectionAngle(double lon1,double lat1,double lon2,double lat2){

[0032] double lon1_rad=lon1*C_PI / 180.0;

[0033] double lat1_rad=lat1*C_PI / 180.0;

[0034] double lon2_rad=lon2*C_PI / 180.0;

[0035] double lat2_rad=lat2*C_PI / 180.0;

[0036] doubledelta_lon_rad=(lon2-lon1)*M_PI / 180.0;

[0037] double y=sin(delta_lon_rad)*cos(lat2_rad);

[0038] double x=cos(lat1_rad)*sin(lat2_rad)-sin(lat1_rad)*cos(lat2_rad)*cos(delta_lon_rad);

[0039] doubledirection_rad=atan2(y,x);

[0040] doubledirection_deg=direction_rad*180.0 / M_PI;

[0041] if(direction_deg<0){

[0042] direction_deg += 360.0;

[0043] }

[0044] return direction_deg;

[0045] }

[0046] S3, calculating the moving distance of the ground target in adjacent set time intervals according to the two three-dimensional coordinates of the ground target in adjacent set time intervals, and calculating the moving speed of the ground target according to the set time intervals.

[0047] Specifically, the calculation formula for the moving distance is:

[0048]

[0049] Wherein, d is the moving distance, r is the radius of the earth; (lat1, lon1) and (lat2, lon2) are respectively the two longitude and latitude coordinates of the adjacent set time intervals;

[0050] Δlat=lat-lat1 is the dimensionality difference;

[0051] △lon=lon2-lon1 is the difference in longitude.

[0052] Then, based on the set time interval, that is, the time interval for the UAV to collect images of ground targets, the moving speed can be obtained by dividing the distance by the time interval.

[0053] In summary, a method for monitoring the motion of ground targets by UAV is provided, in which a monocular UAV is used to locate ground moving targets by taking photos at equal time intervals. The premise of the present invention is that the three-dimensional coordinates of the target in each photo have been obtained, and the time interval between the photos taken by the UAV during flight is known. The present invention can obtain the motion direction and speed of the target through certain calculations.

[0054] In the several embodiments provided by the present invention, it should be understood that the disclosed method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the above units is only a logical function division. There may be other division methods in actual implementation. For example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0055] The above-mentioned integrated unit implemented in the form of a software functional unit can be stored in a computer-readable storage medium. The above-mentioned software functional unit is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor (Processor) to perform some steps of the above-mentioned method of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (Read-Only Memory, ROM), random access memory (Random Access Memory, RAM), disk or optical disk and other media that can store program codes.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for monitoring the motion of a ground target by using an unmanned aerial vehicle, characterized in that: The method comprises: S1, obtaining the three-dimensional coordinates of the ground target in the earth coordinate system according to the set time interval; S2, based on the conversion relationship between the earth coordinate system and the horizontal plane coordinate system, according to the two three-dimensional coordinates of the ground target in adjacent set time intervals, calculating the horizontal plane movement direction of the ground target; S3, calculating the moving distance of the ground target in adjacent set time intervals according to the two three-dimensional coordinates of the ground target in adjacent set time intervals, and calculating the moving speed of the ground target according to the set time intervals.

2. The method for monitoring ground target motion by a UAV according to claim 1, characterized in that: In S1, the set time interval is the time interval between adjacent video frames of the drone capturing images of the ground target.

3. The method for monitoring ground target motion by a UAV according to claim 2, characterized in that: In S1, the three-dimensional coordinates include the longitude and latitude coordinates of the ground target.

4. The method for monitoring the motion of a ground target by a UAV according to claim 1, characterized in that: In S2, the horizontal plane coordinate system adopts a 360° direction method, with the north direction being 0° and the angle value gradually increasing in the clockwise direction.

5. The method for monitoring ground target motion by a UAV according to claim 4, characterized in that: In S3, the calculation formula of the moving distance is: Wherein, d is the moving distance, r is the radius of the earth; (latl, lon1) and (lat2, lon2) are respectively two longitude and latitude coordinates of adjacent set time intervals; Δlat=lat2-lat1 is the dimensionality difference; Δlon=lon2-lon1 is the longitude difference.

Images